The present invention relates to an optical disk into which information can be written, such as a write-once optical disk or the like, which can be managed so as to protect the copyright of information recorded in a read-only optical disk or the like, for example so as to prevent unjust copying of the information, and relates to an optical disk drive for recording information into the optical disk or reproducing the recorded information.
In recent years, there has been widely used an optical disk for recording various digital information on document, image, video, voice, sound or the like in such a manner that the information can be read using laser rays. The above-mentioned optical disk has various advantages such as higher recording density, shorter access time, higher durability against disturbance due to electromagnetic field or the like, and longer living time, in comparison with a conventional magnetic recording medium such as a magnetic disk or the like. As the optical disk described above, there may be concretely pointed out, for example, a DVD (Digital Versatile Disk) which is suitable for recording video information (AV data) or data for computer use etc., or a CD (Compact Disk) which is suitable for recording audio information or document data etc.
As one of the above-mentioned optical disks, there has been known an optical disk into which a user can write information (hereinafter, called xe2x80x9cwritable optical diskxe2x80x9d)), for example a write-once optical disk into which the user can write information once only (for example, a write-once DVD (DVD-R), a write-once CD (CD-R) or the like). Among the above-mentioned various writable optical disks, the write-once optical disk is suitable for being used as a mass storage file for a document data or image data, because it can stably store the written information for a long time (for example, several ten years).
Meanwhile, as for the conventional writable optical disk such as the CD-R or RW, for example the write-once optical disk, the user can copy information recorded in another optical disk to the writable optical disk by reconstructing a normal optical disk drive with a recording function (writing function). Accordingly, from a physical point of view, the user can arbitrarily copy various information recorded in an optical disk acting as an information source (hereinafter, called xe2x80x9csource diskxe2x80x9d) such as a read-only optical disk on the market, to the writable optical disk.
However, in general, the information recorded in the source disk is a literary property produced by a specified literary worker. In this case, as a rule, the literary worker has a copyright for the information of the literary property, in accordance with the provision of the copyright law or the like. Therefore, such an action as to copy the information recorded in the source disk to the writable optical disk without a just reason, is an illegal action as a rule. Thus, it cannot be denied that the regulation for the above-mentioned action is a matter which should be legally solved by adjusting the legislation for the intellectual properties, on one hand. However, on the other hand, it may be said that the above-mentioned illegal action is caused or facilitated by such a fact that the information of the source disk can be physically copied to the writable optical disk with ease, if an optical disk drive on the market is used. That is, in the conventional optical disk or optical disk drive, there may exist such a problem that it is impossible to physically prevent the information of the source disk from being illegally copied or utilized.
Besides that, in the conventional writable optical disk, there exists also such a problem that it is impossible to sufficiently manage the disk information when the information is read or written, namely it is impossible to sufficiently construct a system for managing the disk information. Because ID (Identification) information for each disk or ID information relating to the information to be recorded into the disk is not treated, the function for protecting the copyright, which includes electronic delivery or the like, is not provided. Therefore, there exists such a problem that it is impossible to construct a system for managing disk information in the electronic information circulation using a communication means such as a network or satellite etc., or to construct an organization for managing information to be read or written except coping organization in the aspect of an organization for managing sensitive information of the user disk.
The present invention, which has been achieved to solve the conventional problems described above, has an object to provide an optical disk or optical disk drive, which can physically prevent the information recorded in the source disk from being copied without a just reason, and further which can sufficiently manage the disk information.
According to the first aspect of the present invention, which has been achieved to solve the above-mentioned problems, there is provided an optical disk, in which (a) requisite information (information to be conserved) of digital type can be written into a recording layer in such a manner that the requisite information can be read using a light, the optical disk including, (b) a data area having a groove extending along a spiral track (getting on the track), the data area being able to record the requisite information in the recording layer within the groove, (c) a lead-in area disposed at a position preceding the data area, the lead-in area being able to record information for managing the optical disk, and (d) a pre-groove area (for example, a test area used for adjusting power characteristics of the optical disk) disposed at a position preceding the lead-in area, the pre-groove area having a pre-groove extending along the track (getting on the track), characterized in that (e) a prepit section is provided at a position corresponding to the track within the lead-in area, the prepit section including at least prepits which have previously stored key information (hereinafter, referred to xe2x80x9ccopy management key informationxe2x80x9d) relating to a regulation (prevention) against copying information into the optical disk, and other prepits which have previously stored information (hereinafter, referred to xe2x80x9cdisk type identifying informationxe2x80x9d) for identifying whether the optical disk is provided with the prepits. Hereupon, the term xe2x80x9cposition precedingxe2x80x9d means a fore position in the direction that the optical pickup moves forward, namely a position of central side of the optical disk.
Hereupon, it is possible that the disk type identifying information includes ID information at every disk. Meanwhile, the prepits may be formed on a substrate in the form of embossment by means of an injection molding process, or may be formed by means of a process using laser rays.
As the above-mentioned optical disk, for example, there may be pointed out a DVD-R, a CD-R, a DVD-RW, a CD-RW, a DVD-RAM or the like.
Hereupon, the lead-in area may be provided with only a prepit section, or provided with both of a prepit section and a groove.
Further, in order to raise the detecting precision of the signals at the prepits, it is preferable that the width of each of the prepits is set to a value that is larger than or equal to the width of the groove, and is smaller than a half of the track pitch (track pitchxc3x97xc2xd greater than prepit widthxe2x89xa7groove width). In addition, it is more preferable that the depth of each of the prepits is set to a value that is approximately equal to the depth of the groove.
In this optical disk, the copy management key information and the disk type identifying information have been previously stored in the prepit section. Therefore, when information in another optical disk is copied to the present optical disk, on the basis of the above-mentioned information, the data information can be prevented from being copied if a predetermined condition for allowing the copy is not satisfied. In consequence, by propagating the optical disk according to the present invention (more preferably, by regulating the use of conventional writable optical disks), it may become possible that the information, which is recorded in each of source disks such as read-only optical disks or the like, is physically prevented from being copied without a just reason.
Further, by combining the copy management key information with the disk type identifying information, it may become possible to sufficiently manage the disk information when the information is read or written. That is, it may become possible to construct a sufficient system for managing the disk information. To be concrete, it may become possible to construct an organization for managing the disk information in the disk publishing, or an organization for managing the reading information or writing information except the copying information in the aspect of the organization for managing the secret information of a user disk. For example, on the occasion of the disk polishing, it may be possible to construct such a disk information management as follows. That is, it is set that only trial information can be read. Then, key information is given on the occasion of purchase. Next, it is verified with a prepit information. After that, the whole information is set to be able to read.
On the above-mentioned optical disk, it is preferable that the recording layer is composed of a vapor-deposited pigment film. In the above-mentioned type of optical disk, the recording layer is necessarily formed on the whole surface of the disk. In this case, if most of the prepits are buried with the recording layer, the detecting precision of the signals at the prepits may be lowered. However, if the recording layer is composed of the vapor-deposited pigment film as described above, the vapor-deposited pigment film is formed in the form of a thin film within each of the prepits. Therefore, most of the prepits are not buried with the recording layer so that the detecting precision of the signals at the prepits may be highly raised.
Hereupon, if the optical disk is a DVD, and further if the DVD is provided with a CSS key area disposed in the lead-in area which stores key information (CSS (Content Scrambling System) key information) for deciphering (de-scrambling) the requisite information, which has been ciphered (scrambled) and recorded in the data area, it is preferable that a partial area including the CSS key area in the lead-in area or all of the lead-in area is formed of prepits. The above-mentioned prepits may be formed on the substrate in the form of embossment, or may be formed by means of a process using laser rays.
That is, in the DVD, in general a control area is provided within the lead-in area, and further the CSS key area is provided within the control area. Thus, the requisite information, which has been ciphered and recorded in the data area, is deciphered using the CSS key information and reproduced. Therefore, it is preferable that a portion of the control area including the CSS key area, all of the control area or all of the lead-in area is formed of prepits so that the CSS key information is prevented from copied.
Hereupon, if the modulation factor of each of the prepits in the above-mentioned optical disk is larger than or equal to 30%, the information of disk can be reproduced using a reproducing apparatus. Meanwhile, it is preferable that the jitter (Data to Clock Jitter) is smaller than or equal to 8%.
According to the second aspect of the present invention, there is provided (a) an optical disk drive (for example, optical disk recorder, optical disk player) which can copy (record) data information recorded in an optical disk acting as an information source (namely, source disk), in which the data information has been previously recorded, to a non-recorded optical disk with pripits according to the first aspect of the present invention, the data information being a requisite information, the optical disk drive being characterized in that it includes (b) an information copying inhibiting means which reads key information relating to a copying regulation, stored in a pripit section of the non-recorded optical disk with the prepits and copyright information relating to a copyright (hereinafter, merely referred to xe2x80x9ccopyright informationxe2x80x9d), recorded in the source disk to compare the both with each other, and then inhibits the data information from being copied if the key information and the copyright information do not satisfy a predetermined conformity condition (matching condition) Hereupon, as the source disk, for example, there may be pointed out a read-only DVD, a recorded write-once DVD, read only CD or the like.
In the optical disk drive, it is preferable that it is further provided with a copyright information writing means for writing the copyright information in the source disk, or information formed by combining (hybridizing) the copyright information with the information stored in the prepit section, into the optical disk with the prepits, when the data information recorded in the source disk is copied to the optical disk with the prepits.
In the optical disk drive, it is physically impossible to copy the information in the source disk to the optical disk with the prepits, if the copy management key information in the optical disk with the prepits and the copyright information in the source disk do not match to each other. Therefore, if the above-mentioned conformity condition is set to such that the condition is satisfied only when the information of the source disk is permitted to be copied into the optical disk with the prepits, the information recorded in the source disk can be physically prevented from being copied to the optical disk with the prepits without a just reason. Further, it may become possible to sufficiently manage the disk information when the information is read or written. That is, it may become possible to construct a sufficient system for managing the disk information.
According to the third aspect of the present invention, there is provided with an optical disk drive (a) which can reproduce data information recorded in each of a read-only optical disk and a recorded optical disk with prepits according to the first aspect of the present invention, to which the data information has been copied using an optical disk drive according to the second aspect of the present invention, the optical disk drive being characterized in that it includes (b) an optical disk type judging means for judging whether an optical disk from which recorded data information is to be reproduced is the read-only optical disk or the recorded optical disk with the prepits, and (c) a means for inhibiting the recorded data information from being reproduced, wherein if the optical disk from which the recorded data information is to be reproduced is the read-only optical disk, the recorded data information is allowed to be reproduced when the read-only optical disk does not store key information for inhibiting reproduction thereof, but the recorded data information is inhibited from being reproduced when the read-only optical disk stores the key information for inhibiting reproduction thereof, while if the optical disk from which the recorded data information is to be reproduced is the recorded optical disk with the prepits, copyright information relating to a copyright and key information relating to a copying regulation stored or recorded in said optical disk with the prepits are read and compared with each other, and then the recorded data information is inhibited from being reproduced when the both do not satisfy a predetermined conformity condition. Hereupon, as the read-only optical disk, for example, there may be pointed out a read-only DVD, a read-only CD or the like.
Hereupon, the optical disk drive according to the second aspect of the present invention and the optical disk drive according to the third aspect of the present invention may be integrally constructed.
In the optical disk drive, when the information in the recorded optical disk with the prepits is reproduced, reproducing the recorded information is inhibited if the copy management key information and the copyright information do not satisfy the conformity condition. Therefore, if the information, which has been inhibited from being copied to the optical disk with the prepits, is copied to the optical disk with the prepits by mistake, it is physically impossible to reproduce the recorded information. In consequence, the copyright as to the information recorded in the source disk can be strongly protected. Further, it may become possible to sufficiently manage the disk information when the information is read or written. That is, it may become possible to construct a sufficient system for managing the disk information.